Electricity meters that measure energy consumption or power consumption typically connect between a utility power line and a load. For example, an electricity meter for a residential customer is often connected at the point at which the electrical system of the residence connects to the utility line. The meter may thereby perform measurements regarding the energy consumed by the load.
Utility meters often include one or more electrical contacts across which a significant amount of current flows. For example, meters often have blades that connect across the power line to enable the measurement of load current and load voltage from within the meter. The blades are received by the jaws of a meter mounting device of the building. The jaws use spring compression to retain the blades securely. If the meter is to be replaced or repaired, the meter may be pulled out of the mounting device, and hence the blades out of the jaws. Although the blades and jaws are usually mechanically robust, they are nevertheless subject to wear, and possibly corrosion. This is particularly the case if the meter has been removed or replaced several times. If wear on the jaws is significant, or if the jaws have corrosion, then there is a possibility of introducing a non-trivial resistance at the jaw/blade connection, which is undesirable. Similarly it is possible for the spring used to effect jaw compression to lose some force with aging or heating over time resulting in a reduction of jaw compression force.
Likewise, certain meters have switches that allow for disconnection of electrical service to a load. For example, many meters allow for remote switching off of the load. Such switches necessarily must have substantial contacts because they carry the entire current of the load when the switch is closed. If these switches are used with some frequency, then there is a potential for degradation. Degradation of the switch contacts increases the resistance over the switch contacts. Such resistance creates additional power loss within the meter, which is undesirable.
Because it is undesirable to introduce resistance at the meter/socket connections or service switch connections, there is a need for a way to detect possible degradation of such connections over time.